The present invention relates to liquid crystal display devices and method of manufacturing the same.
This application is a U.S. national phase application of PCT International application PCT/JP99/01510.
The manufacturing of liquid crystal display devices includes a series of processes of configuring a liquid crystal cell using substrate 1 on which an electrode pattern as shown in FIGS. 6 and 8 is formed , cutting and removing the periphery of this liquid crystal cell at cut position 2, and polishing the cut section to smooth the rough surface.
Terminal electrode 3 is formed near the cut position of substrate 1 for connecting to an external circuit. A reference numeral 6 in FIGS. 6 and 8 shows a display electrode.
In case of an active matrix array substrate having a switching device such as a thin film transistor inside a liquid crystal cell, common electrode pattern 4 for short-circuiting terminal electrode 3 is provided on substrate 1 for preventing destruction of any switching elements by static electricity generated during the manufacturing processes of an array substrate and liquid crystal cell. Common electrode pattern 4 is then removed after cutting the periphery of liquid crystal cell.
Even in the case of a liquid crystal cell not possessing a switching device, a common electrode pattern for short-circuiting the terminal electrode is also provided in order to prevent degradation of an aligning film by static electricity. The common electrode pattern is then removed after cutting the periphery of the liquid crystal cell.
These electrodes are conventionally formed with an ITO (indium tin oxide or tin oxide solid solution). In this case, as shown in FIGS. 5(a) and 6, common electrode pattern 4 is automatically removed when cutting the substrate by providing common electrode pattern 4 outside cut position 2.
However, recent demands for larger displays require a lower resistance electrode. For example, the Japanese Patent Laid-open Publication No. H9-230806 proposes the use of an Ag metal electrode.
In addition, for increasing the brightness of a reflective liquid crystal display device as a mobile display apparatus, provision of a reflector inside the liquid crystal cell is proposed by forming a metal electrode functioning both as a reflector and electrode on a bottom substrate. This configuration uses a signal polarizer or no polarizer. As for materials of the metal electrode, Al and Ag materials are receiving attention because they have low wiring resistance and high reflectance (e.g., the Japanese Patent Laid-open Publication Nos. H7-134300 and H8-179252).
However, the use of the metal electrode as terminal electrode 3, in particular Al and Ag materials which are not hard metals, may short-circuit the adjacent terminal electrodes at the cut section of the substrate during polishing due to the ductility of the terminal electrode material, as shown by a reference numeral 7 in FIG. 5(b), where adjacent terminal electrodes are intended to be electrically isolated as shown in FIG. 5(a), as a result of the cutting and polishing processes of the liquid crystal cell.
To avoid the above short-circuiting, common electrode pattern 4 is provided inside cut position 2 of the substrate, as shown in FIG. 8, and an additional process of separating terminal electrodes by removing common electrode pattern 4 (an area equivalent to laser irradiation width L) by laser irradiation, as shown in FIG. 7, is required after cutting the periphery of the liquid crystal cell.
The present invention aims to offer a liquid crystal display and a method of manufacturing the same which eliminate an additional process such as laser irradiation even when an electrode pattern is formed using a ductile metal material.
The liquid crystal display of the present invention comprises a first substrate; a terminal electrode made of metal provided inside the first substrate; an intermediate connection wiring made of metal whose one end is connected to the terminal electrode and the other end reaches to a substrate end; a second substrate; and a liquid crystal layer interposed between the first and second substrates. The width of the intermediate connection wiring at the end of the first substrate is set to be narrower than the electrode width of the terminal electrode.
A method of manufacturing the liquid crystal display of the present invention includes the steps of
forming two or more terminal electrodes made of metal on the first substrate inside a cut position for cutting and removing the periphery of the substrate at a later process;
forming the common electrode wiring outside the cut position;
forming the intermediate connection wiring made of metal for connecting each terminal electrode to common electrode wiring, whose width is narrower than that of the terminal electrodes at the cut position;
interposing liquid crystal between the first and second substrates; and
cutting and removing the periphery of the substrate at the cut position of the first substrate.
The present invention thus provides a liquid crystal display which does not cause short-circuiting between adjacent terminal electrodes even when the substrate end is polished after cutting the substrate on which the electrode pattern made of ductile metal is formed.